Sheryl Sandberg may be one of the most influential executives in the world now, but there was a time when social media's bigwig was just starting out. Her first boss recalls when she was fresh out of college

Lant Pritchett: 'I'm not sure she learned anything from me as a boss.' Photograph: Patrick Fraser for the Guardian. Click for full portrait Patrick Fraser/Guardian

Sheryl was working in Larry Summers's office at the World Bank, but he was busy most of the time, so I guess I was an intermediary boss. This was her first job out of college. She had been a student of Larry's at Harvard; he had moved to the bank and she joined after graduation. She was his assistant, which meant she did everything from writing speeches to putting together data. She also did some other work with the World Bank and ended up going on some project missions; she went to India on a health project.

Her plan was to work a while, then go back to school to study law. I spent a fair amount of effort talking her out of it on the premise that, having seen her work, she was destined to run the world. I tried to convince her that what lawyers did was get deals done for people who were making deals, and she should be in charge of the deals and have lawyers work for her. She should go and get a business degree that would prepare her to run the world. It took about three or four weeks to realise that this young woman was going to surpass me very fast.

She was young, brilliant, good-looking, and you might easily bridle at that, but she is so good at working with people, you couldn't help but like her. Even during her first month, we got into a discussion about something. She was a kid fresh out of college; I had a PhD and four years' experience at the bank. We would argue, and she would go away, and the next day she would come back with an even better argument. All done in a way that the more she argued with you, the better you liked her.

One of the stories she tells in her book is the first thing Larry asked her to do, which was to calculate the rate of growth of real wages in the US. She asked me, "How would I do it?" I said, "Key these numbers in, and once you've keyed them in, come back and I'll show you the command." She said she didn't know how to do that, to which my response was, "Wow, I'm surprised you could finish Harvard not knowing how to do that." In the book, she says she went home, called her mother and cried that she was going to get fired. But the next day I showed her how to do it and she got it.

I'm not sure she learned anything from me as a boss. I'm an academic. Everybody that I'm the boss of is sitting in my office right now, and there's nobody here. She might have learned some things from me, but none of them was leadership-related – those are skill sets she just has. She is way far from done.